1. Field of the Invention
The present invention relates to an electrophotographic image forming apparatus. More particularly, the present invention relates to an electrophotographic image forming apparatus having a separator that separates a printing medium from a transport belt.
2. Description of the Related Art
Typically, an electrophotographic image forming apparatus receives digital image data, and forms a corresponding latent electrostatic image by exposing a photoconductor to a light beam scanned from a laser scan unit (LSU). The latent electrostatic image is developed on the photoconductor into a visible toner image by using toner. The visible toner image is transferred to a printing medium. The toner image is fused on the printing medium by applying heat and pressure to form a predetermined image.
Electrophotographic image forming apparatuses can be divided into dry and wet types depending on toner and carrier. The dry type electrophotographic image forming apparatuses can be divided into one-phase development types and two-phase development types.
The one-phase development electrophotographic image forming apparatus uses only toner to form an image. The two-phase development electrophotographic image forming apparatus uses the carrier containing the toner to form an image.
In the one-phase development electrophotographic image forming apparatus, a development unit applies the toner to the photoconductor to develop a visible toner image. A cleaning blade removes remaining toner of the photoconductor after the visible toner image is transferred. A toner collector collects the removed toner to reuse it. In the two-phase development electrophotographic image forming apparatus, a development unit applies the toner of the carrier to the photoconductor to develop a visible toner image. The remaining carrier is collected. A cleaning blade removes any remaining toner of the photoconductor after the visible toner image is transferred. A toner collector collects the removed toner to reuse it. When printing a color image, the remaining toner of the photoconductor is a mixture of several color toners, such that it is hard to reuse the remaining toner.
A color image forming apparatus includes cyan, yellow, magenta, and kara (black) developer cartridges that are sequentially arranged.
The developer cartridges may share one photoconductor or may be respectively provided with more than one photoconductor.
When sharing the photoconductor, the developer cartridges sequentially apply toner to the photoconductor on which an electrostatic latent image corresponding to digital image data is formed. The applied toners are overlapped to form a visible toner image. The visible toner image is transferred to a printing medium by an intermediate transfer unit.
When each of the developer cartridges is provided with the photoconductor, a transport unit is installed to face all the photoconductors of the developer cartridges. Toner images with different colors are sequentially transferred from the photoconductors to the printing medium when the transport unit conveys the printing medium, such that the toner images can be overlapped on the printing medium to form an image.
After the image is formed on the printing medium, the printing medium must be separated from the transport unit. The curvature of a roller of the transport unit enables this separation of the printing medium. However, since the printing medium is charged during the toner image transferring it is hard to separate the printing medium having a thin thickness from the transport unit using the roller's curvature, thereby causing jamming due to non-separation or delayed separation of the printing medium.
Accordingly, a need exists for an improved electrophotographic image forming apparatus that easily separates a printing medium from a transport unit.